Marcos Rafael Armas Ruiz (born August 5, 1969) is a Venezuelan former first baseman in Major League Baseball who played for the Oakland Athletics during the 1993 season. He was listed at and . He is the half-brother of former outfielder Tony Armas and uncle of pitcher Tony Armas Jr.
In one season with Oakland, Armas batted .194 (6-for-31), with one home run, two doubles, seven runs, and one run batted in in 15 games.